03/26/2013 07:56 pm ET Updated May 26, 2013

Gay rights lobby courts lawmakers with cash

By Michael Beckel

As the U.S. Supreme Court hears oral arguments this week in two cases concerning gay rights, advocacy powerhouse Human Rights Campaign has been rallying its base by word -- and by dollar.

"This is our moment," Human Rights Campaign President Chad Griffin wrote Sunday in an email to supporters. "Tuesday is the culmination of years of work. The millions like you who have pitched in, spoken out and recruited friends to our cause have helped bring us to this point, but we're not at the end of this journey yet."

According to the Center for Responsive Politics, the Human Rights Campaign spent $1.37 million on federal lobbying last year -- more than any other group focused on LGBT issues.

The Washington, D.C.-based Human Rights Campaign, which is the largest advocacy group focused on the rights of lesbians, gays, bisexuals and transgender people, also operates a political action committee.

In February, its PAC doled out a combined $7,000 to five members of Congress, according to records filed last week with the Federal Election Commission.

Sen. Mark Begich, D-Alaska; Rep. Bill Foster, D-Ill.; Rep. Raul Ruiz, D-Calif.; and Dirigo PAC, the leadership PAC of Sen. Susan Collins, R-Maine, each received $1,000, records indicate.

Continue this story and read more investigations at The Center for Public Integrity